Jeweler Russ Johnson says such a piece would sell for "a couple of hundred dollars." Johnson owns Florida-based TheChainGang.com, which has sold high-end nipple shields to celebrities, whom he declined to name.

Johnson says nipple shields have been around for at least a decade.

"You wouldn't want to wear one of those while you were dancing with a tight outfit," says Drew Michael, CEO of Tribalectic.com, a body piercing Web site. "It would be quite uncomfortable, which makes me believe (her exposure) wasn't quite an accident."